Health authorities said 28 days with no new cases showed the virus was eliminated from the community, given that period represented two 14-day incubation periods.

But the Department of Health and Human Services on Thursday confirmed coronavirus fragments were detected in wastewater in Corio, near Geelong.

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Residents and visitors to Geelong's northern suburbs and Lara from November 21 to November 23 were urged to get tested if they had any symptoms, no matter how mild.

Acting chief health officer Allen Cheng said the viral fragments could be from residents or visitors who were shedding the virus.

"We have had few of these positive wastewater results recently and, while we haven't discovered any undiagnosed case of coronavirus, it is possible that there may be an infectious person in this catchment," Professor Cheng said.

"We encourage people in this area who are symptomatic to be tested and will update the community once more testing results become available."

Coronavirus fragments were last week detected in wastewater in Altona, Benalla, and Portland.

Despite increased testing of residents and visitors in those locations, there were no further positive COVID-19 cases.

The DHHS data released on Friday showed there were no active coronavirus cases in the state.

There were 9828 people who were tested for the virus on Thursday.